Sheet metal panels serving as automobile door bodies are provided with EA members made of rigid urethane foam for the purpose of energy absorption (EA) in the likelihood of side-on collision. As a method for securing an EA member made of rigid urethane foam to a door-body sheet metal panel, a structure shown in FIGS. 12a to 13b has been disclosed in Japanese Unexamined Patent Application Publication No. 2004-132462.
FIG. 12a is a substantially horizontal cross-sectional view showing an EA-member securing structure disclosed in the aforementioned document. FIG. 12b is a side view of a locking member included in the EA-member securing structure. FIG. 13a is a cross-sectional view for describing a method for manufacturing an EA member provided with the locking member. FIG. 13b is an enlarged view of a part shown in FIG. 13a. 
As shown in FIGS. 12a and 12b, a plate-like EA member 1 made of synthetic resin such as rigid urethane foam is secured with a clip 3 to a component serving as a body sheet metal panel (a door trim in this case) 2. As a lock catching part, a hole 4 is provided in the body sheet metal panel 2. The clip 3 is caught in the hole 4.
The clip 3 has a cylindrical body 6, an anchor 5 projecting outward like a collar from the bottom of the cylindrical body 6, a flange 7 projecting outward like a collar from the top of the cylindrical body 6, and a plurality (two in this embodiment) of projections 8 and 8 projecting in a direction parallel to the cylinder axis of the cylindrical body 6 from the top end face of the cylindrical body 6. The projections 8 and 8 are provided opposite each other in the diametrical direction of the hole 4.
On a side face of each projection 8 with respect to a direction in which the projection 8 projects, a catch 8a projects laterally with a space 9 being provided between the catch 8a and the flange 7. The amount of the lateral projection of the catch 8a gradually becomes larger toward the flange 7. That is, the outer sides of the projections 8 and 8 are tapered. This enables easy insertion of the projections 8 and 8 into the hole 4.
The clip 3 is made of synthetic resin and is generally molded as an integral body. The projections 8 and 8 are resiliently deformable toward each other.
Additionally, in the synthetic resin forming the clip 3, ferromagnetic particles such as ferrite particles are dispersed. Further, the clip 3 is in the magnetized state because of magnetization performed on the ferromagnetic particles. Thus, the clip 3 can be magnetically attracted to and held by a mold used for molding the EA member 1.
As shown in FIGS. 12a and 12b, the cylindrical body 6 and the anchor 5 of the clip 3 are embedded in the EA member 1. In this embodiment, the bottom surface of the flange 7 is flush with the surface of the EA member 1. Alternatively, the top surface of the flange 7 may be flush with the surface of the EA member 1. It is also allowable that the lower half of the flange 7 is embedded in the EA member 1 while the upper half of the flange 7 projects from the surface of the EA member 1. However, if the flange 7 projects from the surface of the EA member 1 as in the case shown in FIG. 12, for example, the positional relationship between the EA member 1 and the body sheet metal panel 2 in a direction toward and away from each other would be uniquely defined by pinching the body sheet metal panel 2 between the flange 7 and the catches 8a. 
By putting the EA member 1 provided with the clip 3 on the body sheet metal panel 2 while inserting the projections 8 and 8 into the hole 4, the EA member 1 is secured to the body sheet metal panel 2. When the EA member 1 is pressed against the body sheet metal panel 2, the projections 8 and 8 are pushed into the hole 4. Since the catches 8a are pressed against the inner periphery of the hole 4, the projections 8 and 8 are bent toward each other and thus are inserted into the hole 4. After the catches 8a have passed through the hole 4, the projections 8 and 8 resiliently restore their original shapes and the sides of the projections 8 are resiliently pressed against the inner periphery of the hole 4, whereby the periphery of the hole 4 being fitted in the space 9 is pinched between the flange 7 and the catches 8a. In this manner, the EA member 1 is secured to the body sheet metal panel 2.
To manufacture the EA member 1 provided with the clip 3, a mold constituted by a lower mold 10 and an upper mold 11 is used as shown in FIGS. 13a and 13b. While the clip 3 is made to be held in a surface of the upper mold 11 facing a cavity, a synthetic resin material is supplied into the cavity and is molded. In the case of using urethane or the like, a formulated concentrate of urethane or the like is supplied into the lower mold 10 and is caused to foam.
The upper mold 11 that holds the clip 3 has a recess 12 that receives the projections 8 and 8 of the clip 3. In addition, a ring member 13 made of a ferromagnetic material (for example, an alloy such as an iron-cobalt alloy or a ceramic material such as ferrite) is provided at the mouth of the recess 12. By magnetizing one of the ring member 13 and the clip 3, the clip 3 can be magnetically attracted to and held by the ring member 13.
After the top surface of the flange 7 is magnetically attracted to and held by the bottom surface of the ring member 13, the above-described molding is performed. After the synthetic resin is hardened to a predetermined degree in the mold, the molded material is removed from the mold. Thus, the EA member 1 with the clip 3 can be obtained. Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-132462
The clip 3 shown in FIGS. 12a to 13b can only be applied to the body sheet metal panel 2 whose thickness matches the space between the flange 7 and the catches 8a. 
That is, if the body sheet metal panel 2 is thicker than that shown in FIGS. 12a and 12b, the catches 8a cannot completely pass through the hole 4 and therefore the EA member 1 cannot be locked to the body sheet metal panel 2. In contrast, if the body sheet metal panel 2 is thinner than that shown in FIGS. 12a and 12b, the EA member 1 wobbles.